Pharmaceutical products or medications are provided in various different forms including liquids, powders, pills and capsules for application. For example, many pharmaceutical products are applied to patients in liquid form by oral administration or injection. The pharmaceutical product usually is provided in a primary package which directly encases the pharmaceutical product. Examples of primary packages are blisters packages, pre-filled syringes, bags and vials.
In connection with primary packaging pharmaceutical products it often is of high importance that certain conditions specific for the pharmaceutical product can be fulfilled. Typically, pharmaceutical products are primary packaged in a sterile manner in order to prevent contamination and degeneration. The primary package including the pharmaceutical product then usually is further packaged, e.g. in carton boxes, for being conveniently transported, sold and the like.
As mentioned, common primary packages include vials and other containers such as syringes, infusion bags and cartridges. Vials typically have a hollow body in which the pharmaceutical product is arranged. The body comprises a neck with an open end which is surrounded by a flange-like edge. For closing vials, often an elastic rubber stopper is placed on the edge of the opening and held by a cap crimped around the rubber stopper and the edge of the body.
In order that the opening of the vial is sealed the rubber stopper has to be tightly arranged on the edge of the opening. For that purpose, it usually is pressed onto the edge such that it is slightly deformed. It is held in a pressed fashion by the cap which typically is made of plastic or metal.
On an industrial level packaging machines are commonly used for primary packaging pharmaceutical products in vials. Thereby, such machines often pneumatically press the rubber stopper together with the cap onto the edge. In this situation the cap is crimped around the rubber stopper and the edge such that a residual force can be held by the cap. Such residual force ensures that the stopper is still pressed on the edge after the vial has left the packaging machine.
Within such packaging processes it is important that the pressure or force applied during and after primary packaging is properly adjusted. On one hand it has to be prevented that when pressing the rubber stopper on the edge of the vial the force is too high such that the edge or the stopper is damaged. On the other hand it has to made sure that after primary packaging the residual force acting from the plunger to the edge is high enough such that the opening is tightly closed in a seal fashion.
For such adjustment modern packaging machines provide information about the pressure or force pneumatically applied, e.g. by a pneumatical cylinder acting on the cap and the stopper placed on the vial. However, for precisely determining the situation such information is not sufficient. For example, the process of crimping the cap applies pressure on the cap and the rubber stopper in addition to the pressure applied by the pneumatical cylinder. However, such additional pressure is not contained in the mentioned information. In consequence, the sum of the pneumatical and crimp pressures can result in a force damaging the stopper, e.g. such that it yields into the opening and the neck of the vial. Or as another example, the rubber stoppers can have different shapes and dimensions such that the pressure applied on the outside of the stopper does not allow for concluding on the force being in fact applied to the edge of the vial.
Therefore, there is a need for a device and a method allowing for gathering information about the conditions of a rubber stopper placed on a edge of an opening of a vial or a similar container for closing the vial or similar container in a precise and predefinable manner.